New data on the Devonian and Carboniferous Graptolithina (Dendroidea) from Belgium with notes on possible occurrences of Rhabdopleuridae in the Belgian Carboniferous

Abstract

An old find of a graptolite from the Eifelian Jemelle Formation, combined with the recent discovery of an exceptionally well-preserved specimen from the Upper Frasnian (Matagne Formation), allow documentation of the geologically oldest and youngest dendroid fossils from the Devonian of Belgium. Both are ascribed to the long-ranging genus Callograptus (Acanthograptidae). These records enlarge the sparse knowledge of graptolite diversity and occurrences along the southern margin of Laurussia during the mid-Paleozoic. In Belgium, Devonian dendroids are exclusively known from the Dinant Synclinorium. The Devonian dendroid faunas previously reported from the Eifelian, Givetian and Frasnian of the Ardenne–Rhenish massifs (Belgium and Germany) are of low diversity (one to five species per locality). The specimens, generally inedaquatelly preserved, were ascribed to the genera Callograptus, Dictyonema, Palaeodictyota?, and Ruedemannograptus? In these massifs, Carboniferous dendroids are only known from the Viséan (Moliniacian) Denée Konservat-Lagerstätte. Other but undocumented reports of dendroids (and rhabdopleurids) are from the historical type area of the Tournaisian Stage (Tournai area, Brabant Parautochthon). Rhabdopleuridae from the Viséan–Serpukhovian of the Campine Basin (Turnhout borehole) remain incompletely known in the absence of the previously described material.